A lot of people who are just getting started ask me what kind of telescope should I buy so that I don’t have to put holes in it, portable?  Refraction?  All kinds of questions in my mind but no one to help answer, and now you just read this article, don’t cross out, please read, this guide will help you understand the classification of astronomical telescopes so that you have a better understanding of the telescope you need.  

(1) Know about astronomical telescopes  

An astronomical telescope consists of an objective lens and an eyepiece. The convex lens or concave reflector near the object is called an objective lens, and the one near the eye is called an eyepiece.  The astronomical telescope can be divided into refraction astronomical telescope, reflection astronomical telescope, refraction astronomical telescope, and radio astronomical telescope.  

(2) Classification of astronomical telescopes  

1. Bottoms up Beer system  

The refracting telescope is the earliest form of telescope.  A combination of several lenses in which light is fed into the front tube and magnified by the refraction of the lens.  But it’s all glass. It’s heavy. The objective end of a refractor telescope is a convex lens, and the eyepiece end is a concave lens (Galilean) or a convex lens (Kepler).  

Compared with Galileo’s telescope, the Kepler telescope has a larger field of view, excellent optical performance, and better imaging effect, so it has become the main optical path system used by refractor telescopes since its invention.  Kepler’s main drawback is that it produces inverted images, so some portable telescopes need to be equipped with a positive optical path system.  

The advantage of refraction telescopes is that they are easy to operate, easy to use, suitable for beginners, but slightly more expensive, but better imaging.  

2. Reflecting Telescopes  

Compared to refracting telescopes, reflecting telescopes use the reflection of mirrors to magnify images. At the bottom of the tube is a concave mirror reflecting light. Because it has only one objective, it is easier to achieve a large aperture.  The focus of the telescope is in front of the primary mirror.  

The advantage of reflecting telescopes is that they have no chromatic aberration and can record information from celestial objects in a wide range of visible light.  But because it also has inherent shortcomings: such as the larger the aperture, the smaller the field of view, the objective lens needs regular coating, and so on.  

The biggest difference between a refracting telescope and a reflecting telescope is the objective lens.  In a refractor telescope, the objective lens is a lens, or a combination of lenses, placed at the top of the barrel that refracts starlight to the focus near the bottom of the barrel.  In a reflecting telescope, the objective lens is a concave mirror located at the bottom of the barrel that reflects starlight to the focus near the top of the barrel.  And reflecting telescopes are easier to make than refracting telescopes  

3. Refraction telescope  

A refraction telescope is an astronomical telescope built with a refraction mirror (rectification mirror) in front of the Cassegrain telescope.  The main difference between the Schmitt – Kassegrin and Maksutov – Kassegrin telescopes is the corrective lens.  

The advantage of the telescopic telescope is that it can obtain a long focal length with a short tube, so it is easy to obtain high system magnification with the eyepiece of the general focal segment.  Compared with a refractor telescope, it can obtain a larger aperture at the same cost.  Compared with reflecting telescopes, the same aperture and overall size can obtain a longer focal length;  

4. Smart trashcan  

Radio telescopes have played an important role in astronomy, including the discovery of cosmic microwave background radiation, quasars, and pulsars.  An electric telescope can map electromagnetic waves into a continuous spectrum by arranging them according to their wavelength.  

Radio telescopes mainly observe radio waves (radio bands) emitted by celestial bodies.  Because the atmosphere has a weak shielding effect on radio waves, the observation of radio telescopes is basically unaffected by the weather, and radio waves have a low requirement on the material of the primary mirror of radio telescopes, it is easier to design and build large aperture radio telescopes than optical telescopes.